46 lines
1.3 KiB
Python
46 lines
1.3 KiB
Python
# -*- coding: utf-8 -*-
|
|
|
|
from __future__ import absolute_import, division, print_function
|
|
|
|
from ._make import _make_attr, _add_methods
|
|
|
|
|
|
@_add_methods(add_repr=False)
|
|
class _InstanceOfValidator(object):
|
|
type_ = _make_attr()
|
|
|
|
def __call__(self, attr, value):
|
|
"""
|
|
We use a callable class to be able to change the ``__repr__``.
|
|
"""
|
|
if not isinstance(value, self.type_):
|
|
raise TypeError(
|
|
"'{name}' must be {type!r} (got {value!r} that is a "
|
|
"{actual!r})."
|
|
.format(name=attr.name, type=self.type_,
|
|
actual=value.__class__, value=value),
|
|
attr, self.type_, value,
|
|
)
|
|
|
|
def __repr__(self):
|
|
return (
|
|
"<instance_of validator for type {type!r}>"
|
|
.format(type=self.type_)
|
|
)
|
|
|
|
|
|
def instance_of(type_):
|
|
"""
|
|
A validator that raises a :exc:`TypeError` if the initializer is called
|
|
with a wrong type for this particular attribute (checks are perfomed using
|
|
:func:`isinstance`).
|
|
|
|
:param type_: The type to check for.
|
|
:type type_: type
|
|
|
|
The :exc:`TypeError` is raised with a human readable error message, the
|
|
attribute (of type :class:`attr.Attribute`), the expected type and the
|
|
value it got.
|
|
"""
|
|
return _InstanceOfValidator(type_)
|